This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Introduction: When nonhuman primates are found to have hair loss (alopecia), this is concerning for veterinarians, researchers, and the public. In addition, regulatory agencies have linked the occurrence of alopecia to the psychological wellbeing of nonhuman primates. Behavioral causes of alopecia have become the default diagnosis for captive primates;however, it is important to investigate the pathogenesis of alopecia including both medical and behavior causes to ensure the most accurate diagnosis and thus, proper treatment. The hypothesis of the study is that typical diagnostic algorithms used in domestic veterinary medicine are not applicable to diagnosing causes of alopecia in nonhuman primates. Methods: Animals that meet inclusion criteria will have the following performed under anesthesia: physical and dermatologic exams;alopecia degree and pattern scoring, using the US National Primate Research Centers Behavioral Management Consortium Alopecia Scoring System. Photographs of 4 views of the affected animal will be taken. Medical diagnostics will include blood draw for complete blood count, serum chemistry, and endocrine panel for hypothyroidism and for hyperadrenocorticism. From alopecic areas, surface skin cytology, dermatophyte culture, deep and superficial skin scrape, aerobic bacterial culture and skin biopsy for histopathology will be performed. Animals will then undergo a subsequent behavioral evaluation, which will include a total of 6 hours of videotaping to look for presence or absence of hair plucking.